The following discussion of the prior art is intended to present the invention in an appropriate technical context and allow its significance to be properly appreciated. Unless clearly indicated to the contrary, however, reference to any prior art in this specification should be construed as an admission that such art is widely known or forms part of common general knowledge in the field.
Pyrrole derivative of present invention is chemically 2-ethoxy-3-(4-(2-(2-methyl-5-(4-(methylthio)phenyl)-1H-pyrrol-1-yl)ethoxy)phenyl)propanoate, which may be optically active or racemic and its pharmaceutically acceptable salts, hydrates, solvates, polymorphs or intermediates thereof. The INN name for pyrrole derivative is Saroglitazar® which is marketed as its magnesium salt of Formula (I), having below chemical structure.

The compound of Formula (I) lower or modulate triglyceride levels and/or cholesterol levels and/or lower density lipoproteins (LDL) and raise HDL plasma levels and hence are useful in combating different medical conditions, where such lowering (and raising) is beneficial. Thus, it could be used in the treatment and/or prophylaxis of obesity, hyperlipidemia, hypercholesteremia, hypertension, atherosclerotic disease events, vascular restenosis, diabetes and many other related conditions. The compound of Formula (I) are useful to prevent or reduce the risk of developing atherosclerosis, which leads to diseases and conditions selected from arteriosclerotic cardiovascular diseases, stroke, coronary heart diseases, cerebrovascular diseases, peripheral vessel diseases and related disorders.
U.S. Pat. No. 6,987,123 B2 discloses novel heterocyclic compounds, their preparation, pharmaceutical compositions containing them and their use in medicine. The patent discloses different pathways for the synthesis of pyrrole derivatives.
U.S. Pat. Nos. 7,041,837 B2, 7,323,491 B2, 8,110,598 B2, 8,212,057 B2 disclose different pyrrole derivatives and their intermediates.
International (PCT) Publication No. WO 2012/104869 provides the use of compound of Formula (I) for the treatment of lipodystrophy.
International (PCT) Publication No. WO 2014/195967 discloses process for the preparation of saroglitazar and its pharmaceutically acceptable salts thereof.
International (PCT) Publication No. WO 2015/029066 discloses polymorphic form of saroglitazar free acid and its pharmaceutically acceptable salts thereof.
International (PCT) Publication No. WO 2015/033357 discloses an improved process for the preparation of saroglitazar magnesium.
The different physical properties exhibited by polymorphs affect important pharmaceutical parameters selected from storage, stability, compressibility, density and dissolution rates (important in determining bioavailability). Stability differences may result from changes in chemical reactivity (e.g., differential hydrolysis or oxidation, such that a dosage form discolors more rapidly when comprised of one polymorph than when comprised of another polymorph), mechanical changes (e.g., tablets crumble on storage as a kinetically favored crystalline form converts to thermodynamically more stable crystalline form) or both (e.g., tablets of one polymorph are more susceptible to breakdown at high humidity). Solubility differences between polymorphs may, in extreme situations, result in transitions to crystalline forms that lack potency or are toxic. In addition, the physical properties of the crystalline form to that of an amorphous form may be important in pharmaceutical processing. For example, an amorphous form may provide better bioavailability than the crystalline form.
Therefore, it may be desirable to have an amorphous form of drugs with high purity to meet the regulatory requirements and also highly reproducible processes for their preparation.
In view of the above, it is therefore, desirable to provide an efficient, more economical, less hazardous and eco-friendly process for the preparation of saroglitazar magnesium having high purity. However, the present invention provides a process for the preparation of saroglitazar magnesium and compositions thereof suitable for development of finished formulations having high purity.